The present invention relates to an image forming apparatus and method in which the image signal obtained by scanning the document is stored and then used to form an image of the document stored signal.
A thermal transfer type copying machine which makes a color copy of a document by using thermal transfer ink ribbons with a plurality of colors is known as an example of such an image forming apparatus. In the conventional apparatus, the document is read by an optical scanner, and the image signal obtained by scanning the document is converted to color component signals representing the color components equal to the colors on the ink ribbon. All the color component signals are stored in a memory and, then, read out sucessively for each color with the result that images of each color are superposed and thermally transferred onto a single copying paper so as to form a full color copy of the document. To reiterate, the entire image signal obtained by scanning the document is stored in a memory and, then, read out and transferred onto a copying paper in the conventional apparatus, leading to a slow copying operation. Where more than one copy of the document is to be made, the second copy et seq. can be formed from the color components stored in the memory. However, the time for obtaining the first full color copy is longer than the time for obtaining the second copy et seq. by the time required for scanning the document.